Temperature control system



Sept. 15, 1936.

P. W. CUMMINGS TEMPERATURE CONTROL SYSTEM Fild Feb. 3, 1952 3Sheets-Sheet l Iii v INVENTOR h Prest on "(Cummings BY ATTORNEYS Sept.15, 1936. P. w. CUMMINGS TEMPERATURE CONTROL SYSTEM Filed Feb. 5, 1932 vINVENTOR 15,; Preston W-Cummzngs BY ,K' Zw gMQQQ ATTORN EYS Sept. 15,1936. p w CUMNHNGS 2,054,071

TEMPERATURE CONTROL SYSTEM- Filed Feb. 5, 1952' 5 Sheets-Sheet 3INVENTOR Pres ton Wcummrgs gag/1' 2 K 4 'ATTORNEYS Patented' Sept. 15,1936 UNITED STATES PATENT OFFICE TEMPERATURE CONTROL SYSTEM Preston W.Cummings, Rockford, 111.; assignor to Howard D. Colman, Rockford, Ill.

'The invention relates to a system of temperature regulation involvingthe operation of a plurality of fluid control devices such as valves anddampers in a predetermined sequence; and the general object of theinvention is to provide an effectual operating mechanism for suchdevices which is capable of being manufactured at a low cost, and isrelatively compact.

A further object is to provide for the successive operation of aplurality of fluid control devices in one direction or the other bymeans of an operating mechanism actuated by a. single electricallydriven operator.

The invention is especially applicable to teml5 perature regulatingsystems of the type which includes a damper for regulating the supply ofair to a room, and valve means for controlling the supply of a heatingmedium such as steam to a heater unit for the purpose of modifying thetemperature of the air thus supplied; and a further object is to providefor a graduated and accurate control of the room temperature through themedium of an effectual operating mechanism actuated by a single shaftwhich is driven in opposite directions selectively by electric motormeans under the control of a thermostat, in a manner such as to actuatethe damper and the valve successively, but in different orders dependingon the direction of rotation of the motor.

Still another object of the invention is to provide in a temperaturecontrol apparatus having regulating devices including an air damper anda valve for controlling the supply of a heating medium, thermostaticallycontrolled electric motor means advantageously associated with saiddevices so as to govern the direction and extent of movement thereof inresponse to varying temperature conditions.

In the accompanying drawings, Figure 1 is a fragmentary perspective viewof a unit ventilator having my improved control mechanism embodiedtherein and showing in addition a separate heating unit in the form of aradiator to which heat is supplied under the control of a power drivenoperator, whose operation is initiated by the main control mechanism forthe unit ventilator.

Fig. 2 is a somewhat similar view but showing the construction of theunit ventilator more in detail and including a full schematicillustration of the control system as applied to the operation of twodampers and two steam supply valves.

Figs. 3 and 4 are fragmentary detail views illustrating the damperoperating mechanism.

Fig. 5 is a fragmentary vertical sectional view illustrating theconstruction ofv the steam supply valve for the unit ventilator and themanner of applying the power-driven operator thereto.

In such illustrative embodiment of the invention, 1 designates thecasing of a unit ventilator having in the lower portion thereof a heaterunit 5 8. Arranged above this unit is a fan 9 for drawing air throughthe lower portion of the casing and discharging it upwardly through anoutlet ill. The air thus forced through the casing l is admitted fromthe interior of the room under the 10 control of a damper II, and fromthe exterior of the room under the control of a set of dampers l2. Forconvenience hereinafter, the dampers I and I2 are respectively referredto as the reg;- culating and fresh air dampers. The unit ven- 15 tilatorconstruction is such that the air passing through the casing under thecontrol of the recirculating damper i I must first pass through theheater unit 8 to which steam or other heating medium is supplied underthe control of a valve I3. 20

The dampers II and I2 and the valve i3 are all controlled, according tothe present invention, by means of a single electrically driven operatorl5 (Fig. 1) under the control of a room thermostat l6 (Fig. 2) and insome instances an auxiliary source of heat is provided as by means of aradiator". As herein shown, this radiator is equipped with a controlvalve l8 which is opened or closed by an operator l9 under the controlof the main operator l5.

In the present instance, the dampers II and i2 are interconnected for.operation in opposite directions so that when the recirculating damper Ii is closed, the fresh air dampers l2 are opened, and vice versa; andthe valve I3 is so related to 5 the operator as to be opened when therecircu lating damper is in wide open position and the fresh air dampersclosed, and vice versa. As a result, steam is supplied to the heaterunit 8 only after the supply of fresh air is entirely out off. 40 Theradiator I1 is supplied with heat by the opening of the valve it only incase the heater unit 8 is unable to raise the temperature to thepredetermined point.

Referring now to the means which I have pro- 45 vided for thus operatingthe dampers II and I2 and the valve iii, the main operator l5 comprisesa reversible electric motor 20 (Fig. 2) preferably in the form of a coretype shading ring induction motor having a drive shaft 2| connected 5through a suitable gear train 22 with a main operating shaft 23. Saidmotor and gear train are suitably enclosed within a casing 24 (Fig. 1)which may be conveniently mounted within one end of the casing I of theunit ventilator, with 55 the main operating shaft extended outwardlyfrom the casing in overlying relation to the valve I3.

Rotation of the shaft 23 in either direction causes the dampers H and [2to be operated. The means employed for this purpose comprises a rockshaft 25 (Fig. 2) having suitable bearings in the upper portion of thecasing I and opera tively connected with the main operating shaft 23.Within the casing is a bell crank 26 fast on the shaft in overlyingrelation to the fresh air dampers l2 and having one arm connected bymeans of a link 21 to an operating bar 28 pivotally connecting theseveral dampers. The other end of this bell crank is connected by a link29 to the recirculating damper ll so that in the rotation of the shaft25 in one direction or the other, the dampers II and I2 operatereversely.

The shaft 25 is rocked in the rotation of the shaft 23 in a directiondetermined by the direction of rotation of the motor 20, and to this endthe operative connection employed comprises a crank arm 30 fast on theshaft 25 and connected by a link 3| to an arm 32 loose on the shaft 23.A spring 33 connected with the crank arm 30 tends to impart a limitedrotational movement to the shaft 25 counter-clockwise; that is to say,in a direction to close the fresh air dampers l2 and open therecirculating damper H. Movement of the shaft 25 in the oppositedirection is effected by means of a stop member 34 fast on the shaft 23and adapted to engage with the loose arm 32 at a predetermined point inthe rotation of the shaft 23 in a clockwise direction. The point atwhich movement of the shaft 25 occurs to close the recirculating damperand open the fresh air dampers is such as to permit the advanceoperation of the valve l3 into closed position; and, on the other hand,movement of the shaft 25 by the spring 33 in a direction to open therecirculating damper and close the fresh air dampers occurs in therotation of the shaft 23 in advance of the operation of the valve l3into open position.

In the present instance, the valve I3 is actuated positively by means ofa cam 35 fast on the main operating shaft 23 and a slotted follower 36connected with a valve stem 31 (Fig. 5). The cam is of the open facetype and acts upon oppositely disposed follower rollers 38, the followerhaving a pin-and-slot connection 39 with the valve stem. A stiff spring40 enclosed within a tubular portion of the follower is adapted to becompressed to hold the valve member 4| against its seat with a yieldingpressure, and another spring 42, interposed between the bonnet 43 of thevalve and a washer 44 at the lower end of the follower, serves to holdthe lower follower roller 38 in contact with the cam. The spring 40employed in the motion-transmitting connection between the follower andthe valve is of course, made of such strength or stiffness that themovements imparted to the valve mem her are positive in effect. The lobeof the cam 35, it will be observed, has a dwell surface .35 effective tohold the valve member 4| against its seat while the shaft 23 is rotatingthrough approximately one quarter of a revolution to actuate the dampersII and I2, thus providing in effect a lost motion connection between theshaft and the valve during which the dampers are operated.

When the parts are in the relation shown in broken lines in Fig. 3, thedampers II and I 2 are held in open and closed positions respectively bythe spring 33 acting upon the rock shaft 25. Assuming that at the sametime the shaft 23 is in a position such as to hold the valve I3 open, itwill be seen that if the shaft 23 is rotated in a clockwise direction(Fig. 3), it will cause the valve member 4| to be lowered against itsseat (Fig. 5), and during this movement, the stop member 34 on the shaft23 will move toward the loose arm 32. Then, as the valve member reachesits closed position, the stop member will move into engagement with theloose arm 32. In the continued rotation of the shaft, the arm 32 isswung upwardly against the action of the spring 33 so as to rock theshaft 25 and close the damper II and open the dampers l2, the positionof the parts at the end of such operation being shown in full lines inFig. 3.

In the reverse operation, the dampers II and I2 will, of course, beoperated first into open and closed positions respectively, andthereafter the valve member 4| will be caused to move into openposition. Thus, it will be seen that when the supply of fresh air isentirely out off and recirculating air only is being drawn through theapparatus, steam is supplied to the heater unit 8; and that when therecirculating damper has been closed and the fresh air dampers opened,the supply of steam to the heater unit is cut off by reason of theclosure of the valve l3 in advance of such operation of the dampers.

I he motor 20 of the power unit l5 comprises briefly a stator 45enclosed by a main winding 46 and defining two poles on opposite sidesof a squirrel cage rotor 41. Shifting of the magnetic field around therotor when the winding 46 is excited is produced by the well knownaction of shading coils. These, in the present instance, are arranged inpairs 48 and 49 with the coils of each pair disposed on diametricallyopposite sides of the rotor and connected in series relation. When themain winding 46 is excited from a source 50 of alternating current, therotor will revolve in one direction when the shading coils 48 are shortcircuited, and in the opposite direction when the coils 49 are shortcircuited.

Selective short-circuiting of the shading coils 48 and 49 is effectedunder the control of the thermostat I6 which has two switches 5| and 52with a common terminal connected by a conductor 53 to ground. Theinsulated switch terminals of the thermostat are spaced apart so thatboth switches may be openedand thus both sets of shading coils renderedineffectual simultaneously. These terminals are connected respectivelyto the coils 48 and 49 by conductors 54 and 55, and interposed in saidconductors respectively are two switches 56 and 5'! controlled by twonotched disks 58 and 59 fast on the main operating shaft 23. Theswitches 56 and 51 constitute limit switches for determining the extentof operation in either direction.

Closure of the thermostat switch 52 in response to a rise in temperatureabove the predetermined point, renders the shading coils 49 effective tocause rotation of the shaft 23 in a clockwise direction; and closure ofthe thermostat switch 5|, in response to a drop in temperature below thepredetermined point, renders the shading coils 48 effective to causerotation of the shaft 23 in a counterclockwise direction. Thus thedirection of movement of the dampers H and I2 and valve I 3 isdetermined by the selective closure of the thermostat switches accordingto temperature conditions. However, the rate of movement of such devicesin either direction is slow and thererent source by a conductor Bl.

fore subject to interruption by movement of the thermostat tongue intoneutral position. As a result of this arrangement, time regulatingdevices operate under the control of. the thermostat to correct anyexcess or deficiency in heat supply, and tend to assume positions suchas to maintain the set temperature through a proper throttling action ofthe dampers and valve, it being observed that the valve member 4| is atall times under the control of its actuating cam 35 so as to bepositively held against steam pressure in various throttling positions.

In cases where the separate radiator I1 is employed, the valve I 8 isactuated by its operator l9 under the control of the main operator l5.To this end, the main operating shaft 23 has a cam 60 thereon adapted tocontrol two switches 6| and M having a common terminal and governing theoperation of the auxiliary operator I9.

Said auxiliary operator l9 comprises a motor 62 of the same generalcharacter as the motor 20 but non-reversible. Its shaft 63 is connectedby a suitable gear train with a shaft 64 having fast thereon a cam 65which acts through a follower 66 to operate the reciprocable valvemember 61 of the valve l8. Successive opening and closing cycles areinitiated by two starting switches 68 and 68, respectively, controlledby cams l and H on the shaft 64, and upon the initiation of eithercycle, a switch 12 controlled by a notched disk 13 maintains the circuitto the motor closed until the end of the cycle, thereupon interruptingthe same. The main winding "of the motor is connected by a conductor 15and branch conductors I6, 11 and 18 to the movable terminals of theswitches 68, 69 and 12 respectively. The stationary terminals of theswitches 68 and 69 are respectively connected by conductors l9 and 80 tothe stationary terminals of the switches GI and GI- respectively, whilethe common movable terminal of said switches is connected to the our-The stationary terminal of the switch 12 is also connected directly tothe source of current by a conductor 82. The arrangement is such thatwhen the valve I3 is in wide open position and the room thermostat I6continues to call for heat, the motor 62 is started under the control ofswitches BI and 68 to open the valve l8. On the other hand, when theroom thermostat ceases to call for heat, the motor is started under thecontrol of switches 6| and 69 to cause the operator l9 to close thevalve I8.

It is to be observed that by employing separate dampers II and I2 only ashort angular movement of the actuating shaft is required to move suchdampers through their entire ranges of movement. During such movement ofthe shaft the dwell surface on the valve actuating cam 35 holds thevalve iii in closed position, and the valve is actuated from open toclosed position during the relatively large remaining portion of theangular movement of the shaft.

I claim as my invention:

1. In an apparatus of the character described, the combination of aheater unit having a control valve, a damper for controlling the flow ofair relative to said unit, a thermostat, and a single electricallydriven operator controlled by said thermostat and including a reverselyrotatable main operating shaft, and separate means,

each driven directly by said shaft and respectively operable on saidvalve and damper while the shaft is rotating in either direction, saidmeans being arranged to actuate said valve and damper in a predeterminedorder.

2. A temperature regulating apparatus comprising a damper forcontrolling the supply of air to a room, means for conditioning the airthus supplied including a fluid control device, a thermostat, anelectric motor controlled by said thermostat, a rotary operating shaftadapted to be driven at slow speed by said motor, a cam on said shaftoperatively associated with said device, and adapted to impart a slowand graduated movement thereto, and a lost-motion connection betweensaid shaft and said damper.

3. In a temperature regulating apparatus, means for supplying air to aroom including a damper, means for conditioning the air thus suppliedincluding a fluid control valve, a thermostat, a rock shaft operativelyconnected with said damper and biased to rotate in one direction, a mainoperating shaft having a member loose thereon operatively connected withsaid rock shaft, an element on said shaft for actuating said member butmovable a predetermined distance independently of said member, and meanson said shaft for actuating said valve during such independent movementof said member.

4. A temperature regulating apparatus comprising, in combination, dampermeans for controlling the supply of air to a room, means forconditioning the air thus supplied including a control valve having avalve member to be operated, a power driven operator for said valveincluding a rotary operating shaft, a reversible electric motor fordriving said shaft, means on said shaft operable in the rotation thereofin opposite directions to impart positive opening and closing movementsto said valve member, other means operable in the rotation of said shaftto actuate said damper means in a predetermined timed relation to saidvalve, a thermostat for controlling said motor, and means for limitingthe extent of rotation of said shaft by said motor.

5. A temperature regulating apparatus, comprising in combination, dampermeans for controlling the supply of air to a room, means forconditioning the air thus supplied including a control valve having avalve member to be operated, a power driven operator for said valvemember including a shaft, an electric motor for driving said shaft andmeans on said shaft op erable as the shaft is rotated from an initialposition in one direction first to move said valve member positivelyinto closed position and then to hold it in closed position, damperoperating mechanism including a rock shaft, other means operable by themotor shaft and operatively connected with said rock shaft to actuateit, while said valve member is held in closed position, and a thermostatresponsive to said air supply for controlling said motor.

6. A temperature regulating apparatus, comprising in combination, dampermeans for controlling the supply of air to a room, means forconditioning the air thus supplied including a control valve having avalve member to be operated, a power driven operator for said valveincluding a main rotatable shaft, electric motor means for reverselyrotating said shaft, a crank arm on said shaft having a lost-motionconnection with said damper means, a spring tending to move the dampermeans in one direction, means on said main shaft operable during apredetermined rotational movement thereof to move said valve memberpositively into closed position and then to holdit in closed position,and

means operable at a predetermined point in such rotational movement ofthe main shaft to impart movement to the crank arm thereon and therebyto said rock shaft, a thermostat for controlling the direction ofrotation of said motor, and means operating automatically to limit theextent of rotation of said shaft by the motor.

7. A temperature regulating apparatus having an air damper and a heatsupply valve, thermostatically controlled electric motor means includinga rotary operating shaft, a cam fast on said shaft for positivelyoperating said valve, and an oscillatory element fast on said shaft andhaving a lost motion connection with said damper to move it.

8. In an apparatus of the character set forth,

the combination of damper means for controlling the supply of air to aroom, means for conditioning the air thus supplied including a controlvalve having a valve member to be operated, a power driven operatorincluding a rotatable shaft, thermostatically controlled electric motormeans for driving said shaft reversely in opposite directions, meansoperable in the rotation of said shaft from an initial position in onedirection first to move said valve member positively into closedposition and then to hold it in closed position, and other meansoperable in the rotation of said shaft to actuate said damper meanswhile the valve member is held in closed position.

9. In an apparatus of the character set forth, the combination of dampermeans for controlling the supply of air to a room, means forconditioning the air thus supplied including a control valve having avalve member to be operated, a power driven operator including arotatable shaft, thermostatically controlled electric motor means fordriving said shaft reversely in opposite directions, means operable inthe rotation of said shaft from an initial position in one directionfirst to move said valve member positively into closed position and thento hold it in closed position, and other means operable in the rotationof said shaft to actuate said damper means while the valve member isheld in closed position, said valve operating means including a camadapted to move said valve member into closed position with a slow andgraduated movement.

10. A temperature regulating apparatus comprising a heater unit having acontrol valve, two dampers, one controlling the recirculation of airrelative to said unit and the other controlling the admission of freshair, means connecting said dampers for operation in unison but inreverse directions, and a thermostatically-controlledelectrically-driven operator including a rotary operating shaft havingtwo actuating elements thereon, one operatively associated with saidvalve and adapted to move it positively into closed position and theother connected with said two dampers, said elements being arranged tooperate the valve and dampers in a predetermined order.

11. In a temperature regulating apparatus having an air damper and aheat supply valve, the combination of a thermostatically controlledelectric motor driven operator including an oscillatory operating shaft,a cam follower connected to said valve, a cam fast on said shaft andhaving a surface thereon for positively actuating said follower andthereby moving said valve, a dwell surface arranged to engage saidfollower in the further movement of said shaft and maintain the positionof said valve, and means on said shaft having an operative connectionwith said damper for actuating the damper in the oscillatory movement ofsaid shaft during engagement of said follower and said dwell surface.

PRESTON W. CUMMINGS.

